CI: Calorie/Energy Needs (2007)

Citation:

Bartlett RH, Dechert RE, Mault JR, et al.  Measurement of metabolism in multiple organ failure.  Surgery 1982;92:771-779.

PubMed ID: 6812231
 
Study Design:
Time Study
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
To compare data from measured oxygen consumption and carbon dioxide production using a respirometer especially developed for patients on mechanical ventilation (which prohibits use of indirect calorimetry) to calculated REE values and evalute effects of energy balance on outcome.
Inclusion Criteria:
  • SICU admission
  • exisiting or risk for multiple organ failure
  • intubated and mechanical ventilator support with FIO2 > 0.3
  • anticipated to have nutritional problems
Exclusion Criteria:
  • not receiving mechanical ventilator support
Description of Study Protocol:

Recruitment Patients selected from SICU patients during a 1 year period

Design Respirometry was carried out once or twice daily on each patient until the patient was discharged from the ICU.  Data from a typical afebrile day were used to calculated Harris-Benedict, Kleiber and Rutten formulas.  Data from the same afebrile day and from the day of maximum temperature were used to compare to 40 Cal/kg and the Wilmore nomogram.

Blinding used: Outcome measured using an objective test, so criterion met.

Intervention:  NA

Statistical Analysis  Not described

 

Data Collection Summary:

Timing of Measurements: Respirometry measured once or twice daily until the subject left the SICU.  Caloric balance was calculated daily.

 Dependent Variables

  • Caloric balance

Independent Variables

  • Complications
  • Mortality

 

Description of Actual Data Sample:

Initial N: 57 (24 males, 33 females)

Age: Average 57  (range 19-89)

Other relevant demographics: ICU stay averaged 18 days (range 2-106 days). Diagnoses included GI disease (n=11), trauma (n=10), hepatobiliary disease (n=8), pancreatitis (n=3), vascular disease (n=14), other (n=11)

Location: University of Michigan Medical Center, Ann Arbor, MI

 

Summary of Results:

Estimating energy needs by a formula was not well correlated with energy expenditure as measured by indirect calorimetry.

Formula for Estimated Energy Expenditure
Correlation of Measured to Estimated Energy Expenditure
(r)

  Survived Died
Harris-Benedict 0.49 0.49
Rutten 0.49 0.49
Kleiber 0.05 0.19
40 kcal/kg 0.06 0.17

Mortality rate appeared to be correlated with energy balance: 
  • 15 patients had positive cumulative nonprotein for 73% survival rate
  • 28 patients had a cumulative caloric balance between 0 and -10,000 kcal for 39% survival rate
  • 14 patients had cumulative negative energy of > 10,000 calories for 14% survival rate (86% mortality)
  • limited statistical analysis with no p values given
Positive respiratory quotient was noted in patients with positive energy balance.  In order to facilitate ventilator weaning due to extra CO2 load, fat was substituted for carbohydrate in some feedings.
Author Conclusion:

Volumetric respirometry may be helpful in determining energy balance for nutritional therapy.  It is better for patients to be fed too much than too little.

Funding Source:
University/Hospital: University of Michigan Medical Center
Reviewer Comments:

This publication shows it age by failing to provide data and statistical methods that allow the reader to adequately interpret findings.  It is a paper presented at the Thirty-ninth Annual Meeting of th Central Surgical Association, Chicago, ILL, March 10-13, 1982.  In it, investigators discuss the use of the respirometer. This is not an interventional study.  To the authors' credit, descriptions of the instrument's validity and reliability are included. This paper may be useful in demonstrating a clinical relationship between energy deficit and complications and mortality in critically ill patients.  Due to the lack of statistical analysis however, these results should not be generalized.

Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  8.3. Were statistics reported with levels of significance and/or confidence intervals? No
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? ???
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? No
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes